An absorbent article, such as a pants-type diaper, generally includes a front waistline portion to be fitted to the front waistline of a wearer, a back waistline portion to be fitted to the back waistline of the wearer, and a crotch portion to be fitted to the crotch of the wearer.
Leg-surrounding openings into which the legs of the wearer are inserted are formed at both sides of the crotch portion.
Protruding portions (so-called flap portions) are formed in the course of the formation of the leg-surrounding openings. Specifically, the protruding portions are formed in the front waistline portion and the back waistline portion, and protrude outward relative to the crotch portion in a direction perpendicular to a front-to-back direction from the front waistline portion toward the back waistline portion.
Such an absorbent article is folded more than once, and multiple folded absorbent articles are collectively packaged.
The inventors are aware an exemplary method of folding an absorbent article, in which the flap portions are firstly folded toward the front waistline portion or the back waistline portion.
Then, the absorbent article is folded in the middle, in the front-to-back direction of the absorbent article, between the front waistline portion and the crotch portion or between the back waistline portion and the crotch portion, in such a manner that the front waistline portion and the crotch portion face each other or the back waistline portion and the crotch portion face each other (see Patent Literature 1, for example).
Meanwhile, a lengthwise conveying method and a crosswise conveying method have generally been known as suitable for conveying an absorbent article being manufactured.
In the lengthwise conveying method, the front waistline portion and the back waistline portion are conveyed in such a manner as to extend in a cross direction perpendicular to a conveyance direction of the absorbent article.
By contrast, in the crosswise conveying method, the front waistline portion and the back waistline portion are conveyed in such a manner as to extend in the conveyance direction of the absorbent article.
The inventors have discovered that, the aforementioned conventional method of folding an absorbent article has the following problem.
In the lengthwise conveying method, the absorbent article is laid to extend in the conveyance direction and has a shape symmetrical with respect to a center line in the cross direction of the absorbent article.
By contrast, in the crosswise conveying method, the absorbent article has a shape asymmetrical with respect to the center line in the cross direction of the absorbent article.
Accordingly, in order to achieve desired folding, the crosswise conveying method might require necessarily involves more complicated steps than the lengthwise conveying method does.